My Pixel 4a received Android 13 yesterday. So far it seems to be pretty much exactly the same as Android 12, with a few useful background features, but nothing really interesting or useful from the user perspective. There's a description of the changes here, or a deep dive here.

The WiFi / Mobile Data tiles aren't showing again, just the "Internet" tile. You can get the WiFi tile back using Tasker as described on this page, but I haven't found a way to get the mobile data tile working yet. The process on that page installs three apps - Tasker, Tasker Settings, and "Auto Notification", I might end up just leaving everything turned on to avoid the hassle.